1. Field of the Invention
The present invention relates to cooling electrical equipment.
2. Description of the Related Art
FIGS. 1A-B schematically show a cut-away side view of an equipment cabinet 100 of the prior art and a perspective view of an array 106 of electrical fans 108 used in cabinet 100. Cabinet 100 houses equipment components such as, for example, printed circuit boards 102 typically mounted on a rack 104. During operation, boards 102 may generate a significant amount of heat. To protect boards 102 from overheating, cabinet 100 has a cooling system including two arrays 106a-b, with one array placed at the top and another array at the bottom of cabinet 100. Fans 108 of arrays 106a-b provide cool air intake and/or hot air exhaust for cabinet 100. In a typical configuration, relatively cool ambient air is drawn into cabinet 100 by rotating blades of fans 108. The, air then circulates within the cabinet before being exhausted through air vents 110 on the sides of cabinet 100. The air heats up during the circulation as it cools down boards 102. Alternatively, cabinet 100 can be connected to a heat exchanger to form a closed-loop system designed to circulate air without introducing ambient air into the system.
One problem with cabinet 100 is that each fan 108 is a source of electrical noise, which may interfere with electrical signals in boards 102. In addition, fans 108 generate mechanical noise and vibrations. Furthermore, due to a relatively large number of continuously running fans in cabinet 100, it is not unusual that at least one of the fans is broken and requires repair and/or replacement.
The problems in the prior art are addressed in accordance with the principles of the invention by a cooling system, which can be used, for example, for cooling of electrical circuit boards housed in an equipment cabinet. The cooling system includes a flow-rate-amplifying pump configured to introduce ambient air into the cabinet. The pump is a passive device, which has a primary intake and a secondary intake and is designed to convert a small volume of compressed air applied to the secondary intake into a large flow of relatively cool ambient air into the cabinet through the primary intake. In one embodiment, the cooling system is designed to use the heat generated within the cabinet to produce compressed air. The air circulating around the circuit boards heats up and rises to the top of the cabinet, where it is channeled toward an air vent. When the air exits through the vent, it rotates an appropriately placed propeller. The torque generated by the propeller is then used to drive an air compressor, the output of which is coupled to the secondary intake of the air amplifying pump. A cooling system of the invention can provide efficient cooling while generating less noise and/or electrical interference than prior art cooling systems.
According to one embodiment, the present invention is a ventilated equipment cabinet for housing and cooling heat-generating electrical equipment, comprising: (a) an enclosure adapted to house the electrical equipment and having one or more air vents; and (b) a flow-rate-amplifying pump having a primary intake, a secondary intake, and an exhaust port, wherein: the primary intake is connected to an opening in the enclosure; the secondary intake is connected to receive compressed gas from a compressed-gas supply, such that, the compressed gas induces a flow of ambient air from the primary intake to the exhaust port; and the exhaust port is configured to introduce the flow into the enclosure, such that the air heats up as it cools the electrical equipment and exits the enclosure through the one or more air vents.
According to another embodiment, the present invention is an apparatus adapted to ventilate the interior of an enclosure having one or more air vents, the apparatus comprising: (a) a flow-rate-amplifying pump having a primary intake, a secondary intake, and an exhaust port, wherein: the primary intake is adapted to be connected to an opening in the enclosure; the secondary intake is adapted to be connected to receive compressed gas from a compressed-gas supply, such that, the compressed gas induces a flow of ambient air from the primary intake to the exhaust port; and the exhaust port is configured to introduce the flow into the enclosure, such that the air heats up as it cools equipment housed in the enclosure and exits the enclosure through the one or more air vents; and (b) the compressed-gas supply adapted to generate the compressed gas using heated air generated within the enclosure.
According to yet another embodiment, the present invention is a method of cooling heat-generating electrical equipment housed in a ventilated equipment cabinet, comprising applying compressed gas to a secondary intake of a flow-rate-amplifying pump, wherein: the pump has a primary intake, the secondary intake, and an exhaust port; the primary intake is connected to an opening in the enclosure; the secondary intake is connected to receive compressed gas from a compressed-gas supply, such that, the compressed gas induces a flow of ambient air from the primary intake to the exhaust port; and the exhaust port is configured to introduce the flow into the enclosure, such that the air heats up as it cools the electrical equipment and exits the enclosure through the one or more air vents.